\documentclass{article}
\usepackage[x11names, rgb]{xcolor}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows,shapes}
\usepackage{amsmath}
%
%
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{0pt}%
\usetikzlibrary{automata}%

\begin{document}
\pagestyle{empty}
%
%
%

\enlargethispage{100cm}
% Start of code
\begin{tikzpicture}[>=latex',join=bevel,]
\tikzstyle{every state}=[draw=blue!50,very thick,fill=blue!20]%
\node (q0) at (89bp,478bp) [state] {$q_{0}$};
  \node (q6) at (74bp,106bp) [state] {$q_{6}$};
  \node (q5) at (74bp,194bp) [state] {$q_{5}$};
  \node (q4) at (110bp,18bp) [state] {$q_{4}$};
  \node (q3) at (89bp,302bp) [state] {$q_{3}$};
  \node (q2) at (171bp,248bp) [state] {$q_{2}$};
  \node (q1) at (89bp,390bp) [state] {$q_{1}$};
  \draw [->] (q6) ..controls (75bp,130bp) and (75bp,136bp)  .. (75bp,142bp) .. controls (75bp,150bp) and (75bp,158bp)  .. node[auto] {$\tau$} (q5);
  \draw [->] (q6) ..controls (87bp,76bp) and (94bp,59bp)  .. node[auto] {$\tau$} (q4);
  \draw [->] (q5) ..controls (62bp,171bp) and (59bp,164bp)  .. (58bp,158bp) .. controls (56bp,149bp) and (57bp,140bp)  .. node[auto] {$c$} (q6);
  \draw [->] (q4) ..controls (47bp,47bp) and (18bp,58bp)  .. (18bp,106bp) .. controls (18bp,302bp) and (18bp,302bp)  .. (18bp,302bp) .. controls (18bp,331bp) and (41bp,355bp)  .. node[auto] {$\overline{a}$} (q1);
  \draw [->] (q3) ..controls (83bp,267bp) and (80bp,242bp)  .. node[auto] {$\tau$} (q5);
  \draw [->] (q3) ..controls (99bp,266bp) and (107bp,237bp)  .. (110bp,212bp) .. controls (116bp,154bp) and (114bp,85bp)  .. node[auto] {$\tau$} (q4);
  \draw [->] (q2) ..controls (173bp,194bp) and (171bp,113bp)  .. (143bp,54bp) .. controls (141bp,49bp) and (137bp,44bp)  .. node[auto] {$\overline{b}$} (q4);
  \draw [->] (q1) ..controls (89bp,360bp) and (89bp,344bp)  .. node[auto] {$\tau$} (q3);
  \draw [->] (q1) ..controls (113bp,349bp) and (139bp,302bp)  .. node[auto] {$\tau$} (q2);
  \draw [->] (q0) ..controls (89bp,448bp) and (89bp,432bp)  .. node[auto] {$\overline{a}$} (q1);
%
\end{tikzpicture}
% End of code

%
\end{document}
%


